Preheat oven to 350°F (175°C) and grease a 9-inch springform pan.
Mix flour, sugar, baking soda, cocoa, and salt in a bowl. In a separate bowl, whisk oil, buttermilk, eggs, food coloring, and vinegar.
Combine wet and dry ingredients gently, then pour into the pan. Bake for 25-30 minutes. Cool completely.
Beat cream cheese and powdered sugar until smooth. Stir in strawberry puree.
Whip heavy cream to stiff peaks in a separate bowl, then fold into the strawberry mixture.
Spread filling over the cooled cake layer. Chill in fridge for at least 4 hours before serving.